"Simple Green," by a semi-lapsed environmentalist, is a rumination on keepsakes and mementos and how best to Reduce, Reuse, & Recycle them after somebody dies and leaves all their stuff behind -- a life's residue, inevitably destined for the landfill, unless a sentimental collector intervenes. A personal essay/memoir by Deborah J. Lightfoot, author of the "Waterspell" fantasy trilogy.